Chapter 1: Uchiha Yusuke
In a small forest near the Hidden Leaf Village, two young boys were engaged in a fierce hand-to-hand battle. The sharp sound of their strikes echoed through the trees. Despite their age, both were clearly well-trained in taijutsu, their every move swift and powerful, stirring gusts of wind through the woods.
One of the boys wore a tight green jumpsuit and sported a comically round bowl-cut hairstyle. His thick eyebrows were almost alarming, and his nose was noticeably larger than average. He was none other than a young Might Guy.
"Yusuke-kun! It's always such a thrill to fight you," Guy said cheerfully, drenched in sweat. "But watch out! This will be my final move!"
His opponent, a boy with sleek black hair and handsome features, remained calm. His narrow eyes were steady as still water. Dressed in the standard Konoha flak jacket, his forehead protector was tied around his left arm. A red-and-white fan symbol emblazoned on the back of his vest marked his clan—the Uchiha.
"Leaf Strong Fis—" Guy began to shout his attack's name but was cut off mid-sentence by the other boy.
"Wait!" Yusuke raised a hand, signaling a stop.
"What's wrong? Are you scared? Have I finally won in taijutsu for once?" Guy exclaimed with tears of joy in his eyes.
Yusuke responded calmly, "Your focus is too fixed on your opponent. You've lost awareness of your surroundings. Izumi's already here—I need to go home for dinner. Let's call it a day."
Almost as if on cue, a young girl's voice rang out from the forest. "Big Brother! Mom says it's time for dinner!"
From between the trees emerged a little girl dressed in purple. This was Uchiha Izumi, Yusuke's younger sister. She had long, dark hair and bright, expressive eyes that sparkled with energy. Her adorable features were accented by a beauty mark beneath her right eye.
Guy looked disappointed but nodded. He and Yusuke had long agreed that whenever Izumi came calling, their sparring session would end. This rule was set by Yusuke himself—Guy had a tendency to get carried away, never knowing when to stop.
"Alright then! Next time, we'll pick up where we left off!" Guy grinned brightly and waved goodbye before shouting, "Youth!" and sprinting out of the forest. As he passed Izumi, he flashed a dazzling smile and gave her a thumbs-up.
Izumi giggled and returned the gesture. "Good luck!"
As Guy's figure disappeared into the distance, kicking up clouds of dust behind him, Yusuke smiled and shook his head. He walked over and lifted Izumi into his arms. "Come on, Izumi. Let's go home for dinner."
Uchiha Yusuke had lived in the world of Naruto for fourteen years now. He was originally a scientist from Earth who had transmigrated into this world. Back on Earth, he had watched the Naruto anime, so he had a rough idea of the story's events—though many details had long since faded from memory. He hadn't paid much attention to the later, godlike battles, only skimming through them. A lot of information was unclear to him.
However, there was one thing Yusuke remembered vividly—the tragic fate of the Uchiha clan. In just a few years, the clan's prodigy, Itachi Uchiha, would massacre nearly the entire clan in the name of protecting the village, sparing only his younger brother, Sasuke.
Yusuke could never accept such an outcome.
It wasn't just because he now bore the Uchiha name—it was because this life had given him a real family: parents who cared for him, and a sister, Izumi, who meant the world to him. He would never allow anyone to harm them.
To take control of his destiny and protect his loved ones, Yusuke had worked tirelessly to grow stronger. In his previous life as a scientist, he had vast knowledge and an understanding of scientific methods and effective training. With a mindset far beyond his peers, he had trained deliberately since childhood, sharpening all aspects of himself. Compared to most, Yusuke had a massive head start. Combined with his relentless drive, his growth had been nothing short of astonishing.
To others, Uchiha Yusuke was a prodigy, a genius on par with the likes of Kakashi Hatake.
Both Yusuke and Kakashi had recently been promoted to Jonin. However, they didn't interact much—especially since the recent deaths of Obito and Rin had left Kakashi even more distant and withdrawn outside of missions.
That said, Yusuke and Kakashi did share a mutual friend—Might Guy. Perhaps that's something that geniuses have in common: few friends, but the ones they have are rare and trustworthy. And Guy was just that—pure-hearted and dependable.
Yusuke couldn't help but feel a deep sense of regret when it came to Kakashi. Had it not been for the series of emotional blows in recent years, this genius might have surpassed even the greatest shinobi recorded in Hidden Leaf history. Now, Kakashi had all but stopped improving, numbing his wounded heart through endless missions. In Yusuke's eyes, this was nothing short of squandering remarkable talent.
Still, regret aside, Yusuke had little time to concern himself with Kakashi. He was now completely immersed in the world of shinobi. His scientific curiosity drove him to relentlessly study everything about ninja techniques and culture. The rules of this world differed vastly from Earth—for instance, while crossing one's arms might reduce speed on Earth, here, sprinting with arms flung backward somehow made you faster. But knowledge is universal. Methods of research and critical thinking remained effective, and with the expertise Yusuke once possessed as a scientist, he held a significant advantage in studying jutsu and developing scientific training methods.
Cradling Izumi in his arms, Yusuke strolled down a quiet country path, basking in the golden glow of the setting sun, cherishing this peaceful moment with his beloved little sister.
"Big Brother, today a boy said you're not really a genius. I argued with him for so long. He's so wrong—you're amazing!" Izumi pouted indignantly from his arms.
"Oh?" Yusuke chuckled, affectionately flicking her nose. "Next time, just ignore things like that. No need to argue."
"But how could I let that slide? He said you haven't awakened your Sharingan yet and that people only call you a genius because of rumors. He said in the Uchiha clan, you're nothing special!" she huffed angrily.
Yusuke laughed heartily. "You're usually so quiet and polite—since when did you become so competitive?"
"I can be polite about everything else, but no one's allowed to badmouth my brother! You became a jonin at fourteen—even without the Sharingan, you're the strongest genius in the clan. No, in the whole village!" she declared proudly.
Although Yusuke had long surpassed his peers and was already a jonin, he still hadn't awakened his Sharingan. This often led to scornful whispers among certain Uchiha clansmen. The Uchiha were a proud people—sometimes to the point of arrogance—and they held an almost pathological pride in the Sharingan.
Many believed the Uchiha were invincible with their kekkei genkai. To them, no matter how strong Yusuke was, the absence of the Sharingan made him a failure. They truly believed they could defeat him simply because they had the eye.
Yusuke himself had long been puzzled by his inability to awaken it. He'd studied ancient records and conducted extensive research. In the end, he found the key lay in intense emotional stimulus—usually trauma involving a loved one or facing extreme danger. Only through such triggers could the Sharingan awaken.
Understanding this condition, Yusuke could only smile wryly. He had few close friends, and his family had stayed within the village, away from danger. His own strength often allowed him to escape peril, resolving conflicts with ease. As a result, even after reaching jonin-level, he still hadn't awakened the eye.
But Yusuke wasn't overly concerned. After all, his true trump card was something far greater—a weapon that had traveled with him into this world. A weapon not native to the Naruto universe. Deep within his soul, suspended amid roaring flames, hovered a long katana wrapped in burning energy.
The blade gleamed with fiery patterns etched across its length, glowing crimson in the inferno. It was none other than the strongest and oldest flame-type Zanpakutō from Bleach—Ryūjin Jakka.
Normally dormant within Yusuke's soul, the Zanpakutō could be summoned during battle. Over the years, the sword's flame-based nature had subtly influenced Yusuke, enhancing his fire chakra, making it both potent and pure. Leveraging this, he had focused his efforts on mastering fire-based chakra and jutsu.
Still, Ryūjin Jakka was far from tame. Its power was fierce and untamed. Yusuke had only recently unlocked its Shikai state. Yet even this first release significantly boosted his combat ability, allowing him to shine in the Third Great Ninja War, earning him the nickname: Blazing Blade.
When Yusuke and Izumi returned home, a warm dinner was already waiting.
"You're back, Yusuke. Hurry up and eat. You push yourself too hard, training every day like that. You're already a jonin—you don't need to overdo it." Uchiha Hazuki, their mother, welcomed them with a soft smile. She looked to be in her early thirties, bearing a strong resemblance to Izumi, though her beauty carried a more mature grace.
Placing Izumi down gently, Yusuke sat cross-legged at the table and grinned. "A ninja can't afford to relax. A bit of extra effort now might mean the difference between life and death one day."
At his words, Hazuki's expression turned a little somber. "So many have died in this war… so many familiar faces gone from the clan in an instant. I wonder how long the great villages will keep fighting."
"Even as a jonin, the shinobi world is dangerous. Please, always be careful," she added gently.
"I will. Don't worry," Yusuke nodded seriously, then put his hands together and said, "Itadakimasu."
Izumi followed suit. "Itadakimasu!"
In Japanese tradition, one always puts their hands together and says "Itadakimasu" before a meal—a way to show gratitude for the food and those who made it.
After the siblings finished dinner, Hazuki brought out two sets of black clothing.
"There'll be a memorial service tomorrow morning—a solemn ceremony to honor all those from our village who fell in the war. I've prepared your clothes for it. Don't forget to wear them."
"Another memorial…" Yusuke murmured softly.